A well-known electrical connector includes plug and receptacle parts that are joinable to produce electrical connection between pins and sockets carried by the respective parts. The connector parts include heavy metal shell housings which, when the connector parts are mated, provide good protection against external electromagnetic fields that would otherwise induce undesirable electric signals in the cable wires and thus into the equipment to which the cable wires are connected. When the plug and receptacle parts are disengaged, exposed contacts which are directly connected to the cable wires can, at that time, be adversely affected by environmental electromagnetic fields.
U.S. Pat. No. 3,550,065 discloses the use of a metal plate that is received over the open end of a connector part including one or more socket contacts, the plate having openings via which pins from the other connector part can pass during mating of the connector. The grid plate or shield is electrically connected to the connector part casing or outer shell and in this way serves as a means for reflecting and absorbing a significant portion of ambient environmental electromagnetic energy.
The shield described in the referenced U.S. patent is effective for many uses; however, present-day electromagnetic environments are becoming increasingly more severe, both as to intensity and frequency, and the shield openings which are of sufficient size to admit a pin contact also provide a means for access of such energy to the socket contacts. Exemplary of the type of extreme environments within which a connector of this kind may be subjected, in the event of a nuclear explosion, an electromagnetic pulse (EMP) is produced which can, by itself, induce damaging electrical and electronic equipment located at distances from the blast that would be sufficient to protect it from the direct blast effects.